南亚热带不同中幼龄人工林溪流水水质特征

以佛山云勇林场4种类型人工林为研究对象，包括针阔混交林、常绿阔叶林、桉树林和杉木林，分析不同类型人工林溪流水水质特征，并综合评价其水质等级。结果表明，不同类型人工林溪流水pH值为5.93~6.34，均为弱酸性水；同一林龄段中，针阔混交林和常绿阔叶林溪流水中总氮含量均显著低于桉树（Eucalyptussp.）林（P＜0.05）。桉树林和杉木（Cunninghamia lanceolata）林溪流水总氮含量均大于2.0 mg·L-1，超过地表水V类标准限值，为富营养型水质；不同林龄段人工林溪流水总磷含量达到地表水Ⅱ类或Ⅲ类标准。不同林龄段人工林溪流水总硬度、Cd和Hg含量达到饮用水标准，氟化物、Pb、Cu、Zn、Cr6+和As含量达到地表水I类标准。灰色关联度分析和主成分分析表明杉木林溪流水水质最好，其次为桉树林、针阔混交林和常绿阔叶林。

Stream Water Quality of Different Young and Middle Age Plantations in South Subtropics

The stream water quality of needle-broadleaf mixed plantations (MP), evergreen broadleaf plantations (EBP), Eucalyptus plantations (EP) and Cunninghamia lanceolata plantation (CLP) were determined to evaluate the level of stream water quality in different plantations. These plantations were divided into two age groups, 5 to 7-year-old and 9 to 11-year-old. The results were as following: the stream water in all plantations was slightly acid with pH of 5.93-6.34. Streams of MP and EBP had significant lower nitrogen and higher phosphorus concentration than EP. The stream in EP and CLP were eutrophication with total nitrogen concentration higher than 2.0 mg/L, which exceeded level V of environmental quality standards for surface water. The concentrations of trace metals including Cd, Pb, Cu, Zn and Cr6 met the standards of drinking water. Grey relation analysis and principal component analysis showed that stream quality was highest in the CLP, followed by EP, MP and EBP. All stream water in different plantations met the first level of environmental quality standards for surface water. These results could guide the sustainable management of young and middle age plantation.